- Kharg -

A strip of scrubland located in the northern Gulf, about 30 kilometres from the coast, Kharg is home to Iran's largest oil terminal, which accounts for around 90 percent of its crude exports, according to a recent note from the American bank JP Morgan.

In mid-March it was targeted by US airstrikes.

Trump described it as a "crown jewel" for Iran and maintained that every military target on the island had been "totally obliterated", but energy infrastructure was left unharmed.

Kharg experienced major development during Iran's oil boom in the 1960s and 1970s because much of the coastline on the mainland was too shallow to accommodate supertankers.

Tehran has since looked to diversify its export capabilities, including by opening the Jask terminal on its southwestern coast in the Gulf of Oman in 2021, but Kharg remains "a critical vulnerability" for Iran, JP Morgan said.

"It is a cornerstone of Iran's economy and a major source of revenue for the Iranian Revolutionary Guards," JP Morgan added, referring to Iran's well-resourced ideological army.

According to expert Farzin Nadimi, a senior fellow of the Washington Institute think tank, carrying out a military operation would be "very difficult" on an island almost entirely covered with oil infrastructure, pipelines and storage tanks,

"The United States Military can take out Kharg Island at any time if the President gives the order," the White House said in a statement last week.

- Larak -

This small island occupies a particularly strategic position at the narrowest point of the Strait of Hormuz, the key shipping route that Iran has choked shut.

A site for Iranian oil exports since 1987, it also hosts an Iranian military base.

It has come to prominence recently and been dubbed "Tehran's tollbooth" -- a stopping-off point for the handful of vessels that Iran has approved to exit or enter the Gulf.

Ships using this route must pay a substantial fee, according to maritime data company Lloyd's List Intelligence, which invented its nickname.

- Qeshm -

The largest island in the Gulf, Qeshm stretches for around one hundred kilometres across the Strait of Hormuz, dominating the entrance to the Gulf.

It is a popular tourist destination for Iranians thanks to its rare UNESCO-listed rock formations, turquoise waters, mangroves and relaxed atmosphere.

"Qeshm used to be a very poor island, and it's only in the past few years, thanks to tourism, that the economy here has started to come alive," a resident there told AFP in a recent interview.

But it is also heavily militarised, analysts say, including strike capabilities that could be used against shipping in the Gulf or invading US troops.

Iran accused the United States of attacking a desalination plant on Qeshm on March 7 in what it called a "blatant and desperate crime".

- Disputed islands -

Iran claims three disputed islets - Lesser Tunb, Greater Tunb and Abu Musa - in the middle of the Gulf, which are also claimed by the United Arab Emirates.

Along with another islet, Siri, "these islands have been fortified, turned into mini-fortresses with anti-ship missiles", Pierre Razoux from the France-based Mediterranean Foundation for Strategic Studies told AFP recently.

Tehran has stationed contingents of the Revolutionary Guards' naval forces there, which in 2025 deployed new missile systems capable of targeting nearby "enemy bases, ships and equipment", Iranian media reported at the time.

If these islets were "controlled by the United States, it would prevent the Iranians from using them for offensive purposes against maritime traffic," Razoux said.